/NETWORK_MASK=IP_address
Required if you use subnets; otherwise optional.
Specifies the part of the host field of an IP address identified
as the subnet.
The software calculates the default by setting the following:
o The bits representing the network field to 1
o The bits representing the host field to 0
You can divide the host field into a site-specific subnetwork
and a host field. If you use subnets, you must specify a subnet
field.